Delegate root layer scroll offset to android_webview.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 10304771b1a7636484fea342cce24c2707e7bd2e..c21238fd32c52b1f34739d2b2b5bab31896cf351 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -220,6 +220,7 @@
 #include "content/renderer/android/content_detector.h"
 #include "content/renderer/android/email_detector.h"
 #include "content/renderer/android/phone_number_detector.h"
+#include "content/renderer/android/synchronous_compositor_impl.h"
 #include "content/renderer/media/stream_texture_factory_impl_android.h"
 #include "content/renderer/media/webmediaplayer_proxy_impl_android.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebFloatPoint.h"
@@ -2627,6 +2628,13 @@ void RenderViewImpl::didActivateCompositor(int input_handler_identifier) {
   }
 #endif
 
+#if defined(OS_ANDROID)
+  if (input_handler_manager && GetSynchronousCompositor()) {
+    input_handler_manager->SetRootLayerScrollDelegate(
+        routing_id_, GetSynchronousCompositor());
+  }
+#endif
+
   RenderWidget::didActivateCompositor(input_handler_identifier);
 }